Agreed, sounds like the regulator.
Over the years I've been through a few on the Rapier.
If you have a bad battery connection the voltage can climb very high and fry the regulator or rectifier.
A sick regulator can let the voltage climb - this can fry the HT coils, bulbs and the rectifier.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.